Back in the mid-1980s, Infinity Systems, which had just been bought by Harman, introduced the idea of branded, premium in-car audio by offering Infinity audio systems in Chrysler vehicles. Of course, today every auto manufacturer has partnered with an audio company, turning what was once a quaint new idea into a business juggernaut. Lexus has Mark Levinson; Audi has B&O; Porsche and Mercedes have Burmester, Lincoln has Revel, and the very British Jaguar and Land Rover have teamed up with that other quintessential British company, Meridian Audio.
Many of these efforts have produced very good sounding systems. But as prestigious as these audio companies may be, none can claim as long a track record as Meridian in developing the core technologies that are the foundation of today’s in-car audio systems. Specifically, contemporary in-car audio is based on DSP crossovers, active loudspeaker arrays, amplitude and phase correction in DSP, processing stereo signals for playback over more than two speakers, and improving the quality of digital source signals with dithering techniques. Those happen to be the specific fields in which Meridian Audio has unparalleled expertise since the mid-1980s—not for car audio, but for high-end home systems. For example, Meridian was the pioneer in active digital loudspeakers, bringing the first such product (the D600) to market back in 1989. Meridian practically single-handedly invented the category. Meridian’s home-theater controllers included sophisticated algorithms for playing two-channel material through a multichannel speaker array. (Meridian was the first to market with an all-digital multichannel AV controller.) The company was also at the forefront of redithering digital signals, most notably in its professional 518 Mastering Processor. No other company developing in-car audio can lay claim to being a pioneer in all these technologies—technologies that coincidentally are the foundation of modern automotive audio systems.
All of this expertise was brought to bear on the audio system for Jaguar’s new F-Pace SUV. The F-Pace’s top system (three levels of audio quality are available) features a 17-speaker array, one of which is a subwoofer. A pair of tweeters in the dash and another pair in the rear doors handle the treble. The front doors also hold a pair of 80mm midrange drivers as well as a pair of 165mm woofers. A second pair of 165mm woofers fits in the rear doors. Finally, a pair of coaxial speakers mounted in the cargo area provide surround envelopment. The array is driven by a combined 825W of amplification. The active digital system employs DSP crossovers along with a range of digital signal processing technologies. These include Meridian Cabin Correction (a DSP-based system for delivering flat frequency response), Meridian Trifield processing for playback of stereo source material through a multichannel speaker array, and Digital Dither Shaping to improve the sound quality of digital sources. Finally, Dynamic Volume Control adjusts the volume based on vehicle speed and the amount of ambient noise.
The system offers a range of sources including a CD drive, integral HDD to which CDs can be ripped, Sirius satellite radio, and a USB port for portable media devices. The user interface is outstanding, thanks to the 10.2** touchscreen display and large “buttons.” The audio-settings menu provides very fine resolution of bass, and treble and subwoofer level adjustment, which allowed me to dial in just the right tonal balance for different sources. I’ve found that the audio-settings adjustments in most car-audio systems are far too coarse. That is, the smallest available adjustment increment causes too great a change, making it impossible to fine-tune the sound. This common phenomenon also makes it likely that unsophisticated consumers will apply grossly distorted settings. Next time you’re in a rental car look at audio system’s bass and treble settings; you’ll probably find that these controls are turned up to the maximum values. Sad!
In addition to listening to various sources while driving, I compared the F-Pace’s system to my home reference system by parking the F-Pace in my driveway and playing the same reference tracks on both systems less than a minute apart. With just a bit of adjustment, the Meridian system was extremely smooth through the upper-bass, midrange, and treble. The mids were remarkably uncolored, and the treble was beautifully integrated with the upper mids. Commendably, the top end lacked the brightness and metallic character that can make the treble sound like a separate component of the sound. This smoothness and ease is a vital factor in an audio system’s ability to engage the listener, particularly over long periods. A hyped-up treble, designed to give the illusion of clarity in a short demo, quickly becomes fatiguing. The Meridian system’s combination of treble resolution with silky smooth liquidity was musically engaging, and didn’t have me reaching for the volume knob to turn it down. I had several multi-hour listening sessions and didn’t get fatigued.
In the flat positions, the bass and low bass were a bit too prominent for my taste. Fortunately, the fine resolution offered by the bass, treble, and subwoofer controls allowed me to precisely dial-in the perfect tonal balance. The separate controls for the bass and subwoofer levels provided an extra degree of adjustment in getting the bass balance just right. A couple of “clicks” of attenuation restored the bass to a natural level. I suspect that most consumers gravitate, at least initially, to a bit of bass boost. The bass went very low and stayed clean, even at high playback levels. I heard no problem frequencies that stuck out or caused the car to rattle. The bass articulation, pitch definition, and dynamic agility were remarkable for a car-audio system. Even the bass pedals on a Hammond B-3 (Joey DeFrancesco’s Part III) were reproduced with a clear sense of pitch and of individual notes starting and stopping, and an effortless character. On many systems, DeFrancesco’s fleet footwork devolves into an undifferentiated blur. Kickdrum not only had tremendous bottom-end punch, but exhibited excellent transient fidelity as well, with no bloat or overhang. This quality added greatly to the system’s sense of rhythmic precision and drive.
Stereo sources can be reproduced in stereo, or over the entire speaker array with one of three user-selectable multichannel algorithms—Meridian Surround, Dolby, or DTS. Stereo reproduction lacked the “over-the-dashboard” imaging I heard through the multichannel settings. The Meridian algorithm was the most natural sounding, freeing the image from the doors and providing a striking illusion of instruments and voices floating in front of the windshield. In fact, I was shocked by the three-dimensional sense of space and image solidity. The soundstage seemed to exist in front of me, completely detached from the speaker locations. The magic of creating a believable soundstage in such an unlikely environment is owed to DSP, along with the fact that the automotive audio system designer knows the precise positions of the speaker drivers, of all boundaries in the listening environment (the cabin), and of the listeners’ ears. Developers of home audio systems have no such information, making the installed performance more of a crap-shoot.
The top audio system in the Jaguar F-Pace combines Meridian’s sophisticated technology with a high-end audio aesthetic to deliver a listening experience that far exceeds expectations for automotive audio. The F-Pace is pretty spectacular, too.
Designing a High-End Automotive Audio System
I asked the Meridian engineering team to explain the design process and the unique challenges of translating home-audio expertise to the automobile.
How long did it take to design the audio system for the F-Pace?
For a brand new nameplate such as the F-Pace, it took around six years to get from the initial discussions around the ambitions for each level of audio systems to having the system architecture finalized. It sounds like a long time, but this is to ensure we were aligned with the program-development plan at Jaguar.
As with our home products, we believe it’s essential to consider and design each element of the system from source to loudspeaker, and from the cabin environment to the listeners’ ears, using our extensive knowledge of digital signal processing and psychoacoustics.
Are you asked to design the audio system around the particular vehicle’s specifications, or is there a cooperative development effort between Jaguar and Meridian? In other words, is Jaguar willing to make design changes in the vehicle to accommodate the audio system?
The nature of our relationship with Jaguar means we’re able to work closely with their very capable in-house audio team to ensure we can package loudspeakers in optimal positions throughout the cabin. As a result, there’s a three-way dialogue between Meridian, the Jaguar audio team, and Jaguar Design Studio.
We’re closely involved with evaluating and reviewing prototype components and directly support Jaguar with its key supplier relationships.
Innovation of cabin interiors—often with more use of glass and other materials on which it’s impossible to package a loudspeaker—can bring up challenges. Our ten years’ experience in automotive audio, thirty-plus-years of expertise in digital signal processing, plus our pioneering legacy of psychoacoustic research means we are very well-placed to overcome any packaging restrictions to deliver a consistent, authentic experience.
An example of this is our Trifield technology. Trifield, along with the center speaker and our unique surround algorithm, makes it possible for all occupants to hear solid stereo imaging. We extend this further for F-Pace by utilizing rear surround loudspeakers to help subtly recreate the venue or studio in which the recording was made.
Do you have a prototype vehicle in-house that serves as the development platform?
We have fleet vehicles during development, and also have test rigs that simulate speaker positioning within the cabin to test and fine-tune our spatial algorithms.
We’re constantly developing new ways to use DSP and our know-how in reference-level loudspeaker design and amplification to improve the audio experience in the car, and the team at Jaguar/Land Rover are equally keen to facilitate by providing vehicles and components in order for us to demonstrate our developments.
How many engineers work on the project?
From Meridian, around eight engineers, including two designers and a supporting technician will work on any given audio system. For F-Pace, we had a team working on the design and specification of the physical components, others working on implementation of digital technologies, and our product and industrial designers work closely with Jaguar’s Design Studio to ensure the look, feel, and branding of the system meets all requirements.
We believe in a collaborative approach to the final voicing of the system to ensure the performance excels for any style of music in any given environment.
Who performs the final voicing of the system and how is that done?
At our facility in Cambridgeshire, we have a purpose-built Automotive Audio Lab, deliberately located next to one of our reference listening rooms. We can easily and quickly make comparisons between the automotive system and our reference loudspeakers (in this case, the [Meridian] DSP7200 SE).
Tuning the F-Pace happened in a number of stages. We had access to a production-representative vehicle and we meticulously measured its sonic characteristics. The data was then fed into our proprietary analytical software to identify any unwanted resonances, and then we defined and implemented a very subtle and transparent filtering process to ensure that all frequencies were equalized in amplitude and consistent in decay. We use a very similar process with our home-audio room-correction technology.
This gave us a perfectly flat, tight baseline performance and quiet environment into which we implemented and refined our spatial technologies. The target here was to create a consistent and authentic soundstage for all occupants of the vehicle and we achieved this through our Trifield surround technologies, which stem from our Reference Digital Surround Controllers.
Reproducing a realistic soundstage within car interiors has many challenges, but a key advantage is that we understand, within a few centimeters, where the listeners’ ears will be. This affords us the opportunity to make very subtle and precise adjustments, knowing there will be very little movement in the listeners’ positions.
Of course, frequency response is measured carefully in all positions to ensure there is consistency throughout the cabin, and there is a target curve that we achieve. However, the system will always undertake a series of painstaking subjective listening tests, both static and dynamic, to ensure that all possible driving styles and environments are considered. This final “human” process is essential to ensure the system reproduces all instrumentation with a realistic, natural result.
The same “golden ears” responsible for the performance of our Reference home products have the final sign-off of the performance of our in-car systems.